where next for me with energy storage and extra generation

[Joeboy]

We started with a pair of 2.4kWh Pylontechs and that grew to six of 2.4kWh units which is our personal.happy place. In the off months that 14.4kWh of storage is more than enough to see us through a 24hr cycle and not worry. In the better season we utilise that capacity so the PV always has somewhere to go. I typically start the day at around 46%soc and will weather forecast permitting run that down to sub 20% soc before going out.

I consider my Pylontechs, HWT, Storage Heaters and EV battery pack to be individual parts of one large storage system.
HWT stores 12-14kWh
EV stores let's say on a day basis 25kWh although the pack size is 73kWh.
That's 39kWh plus the 14kWh for the Pylontechs. 53kWh potential storage before adding in the 30+ on the SH system. I could then add in the washing nachine and dishwasher. Could easily utilise/store 100kWh in a day if I had that coming in and only 14kWh of that is traditional battery storage.

Essentially, you should sit down with an A4 sheet, split your patterns into Summer and Winter and see how,what and when you are using your current power. Once you have a rough pattern of generation use & export across the two seasons you can have a rough stab at a pack size. Also worth having a think about the next 5 years as you will likely change your behaviour based on the gains you'll see.

[SafetyThird]

Joe, sounds like a solid plan. I'm working through my bills at the moment trying to break it down to daily amounts.

Perhaps I shouldn't have got rid of all the storage heaters over the years

The heat pump has been using 9kwh/day over the past three months so I know I'd like to have double that in battery storage but I'm not sure I can stretch that far financially at the moment but something around 10kwh would be a good start and then get another battery when I can afford it and also consider extra PV on the barn roof, particularly when we move to buying an EV later this year.

I've been with Good Energy for 8 years now but it might be time to look at something like Octopus and their agile options, although they're advising people not to change suppliers currently. Since November 1st, I pay 28.94p day rate and 18.94p night rate with a 47.74p daily standing charge. If I can get a much lower rate with Octopus and utilise it to time shift my power purchases, that would make a big difference to the bills over the next couple of years.

[Joeboy]

Joe, sounds like a solid plan. I'm working through my bills at the moment trying to break it down to daily amounts.

Perhaps I shouldn't have got rid of all the storage heaters over the years

The heat pump has been using 9kwh/day over the past three months so I know I'd like to have double that in battery storage but I'm not sure I can stretch that far financially at the moment but something around 10kwh would be a good start and then get another battery when I can afford it and also consider extra PV on the barn roof, particularly when we move to buying an EV later this year.

I've been with Good Energy for 8 years now but it might be time to look at something like Octopus and their agile options, although they're advising people not to change suppliers currently. Since November 1st, I pay 28.94p day rate and 18.94p night rate with a 47.74p daily standing charge. If I can get a much lower rate with Octopus and utilise it to time shift my power purchases, that would make a big difference to the bills over the next couple of years.

A few of us here on the various Octopus tou tariffs. It works out well and as a bonus keeps me focussed in Winter . You've got it covered by applying a modular approach. The pylontechs can have up to a 7 year warranty if you fill in the online warranty. I am now at 95%soh and the stack is in its 5th year. I run the stack down to 10%soc not 20%. Cheers

[Countrypaul]

I missed thinking about this earlier, but if you have a HP with a thermal store, then depending on your HP you might be able to trigger it via the Eddi when there is excess PV production. The Eddi manual explains how to set it up to do so provided your HP supports it. Once you have a battery system, you will need less tme trying to optimise the Eddi settings as you could draw from the battery rather than grid when a cloud passes over, to avoid short runs.

In our case we have an Ecodan which does support this under certain conditions, but until now I had forgotten about it (not worth trying over winter as too much background demand to be worth triggering). The Ecodan also raises the target temperature by 3 degrees when triggered in this way, but I'm not sure if that applies in our case when using an external thermostat.

[SafetyThird]

Hi Paul, thanks for the thought about the Eddi and the heat pump. I looked at it at the time but I think we decided that as the heat pump runs the hot water, there wouldn't be much extra input from the heat pump itself as the temperature for DHW is set lower than the immersions and the heat pump tends to keep the tank topped up during the day. The Eddi will throw extra energy into the tank and take it higher than the heat pump would. At least, I think that's what was said at the time of the install.

[SafetyThird]

So after a bunch of reading, I thought I'd narrowed it down to two potential systems.

Givenergy 3kw AC inverter with the forthcoming 9.5kwh battery and the Solar ME300ES inverter with 3 of the Pylontech US3000c 3.55kwh batteries. Both systems seem to have similar abilities, capacities and price (approx £4500 plus install) and can be expanded later if needed.

However, if I wanted to expand the batteries, I'd probably need another inverter to gain more than 3kw/h charging rate and be able to fully charge the batteries in the winter during off peak if I was on something like the Octopus tariff with a 4 hour charge window.

watching this video I was surprised to see that Givenergy appear to be incorporating a divert system and some upcoming monitoring options in the near future. Though that might only be with the hybrid inverters rather than just the AC inverter. Also, it touts being able to talk to Octopus for their energy tariff options but that's not something I've explored yet, but might be interesting to consider.

Then, last night, I was watching this video on YouTube,

He's had the Givenergy system on test and ultimately went with the Victron inverter and pylontech batteries. I need to watch it again but he raises points about controllability and logging and shows the Givenergy system only updates every 5 mins which isn't really good enough. The Victron setup seems to have a few additional options and higher power inputs/outputs (5kw) plus Victron have been around for many years with a solid track record and global customer base. Also, you're not tied to any single manufacturer for batteries etc which has some appeal

Bimble solar do a system with 4 of the pylontech batteries and all the ancillaries for £7.2k or likely £6k with three batteries which would be equivalent to the first two in capacity but with seemingly more capability and expandability. I could probably reduce that cost by not having things like the display screen etc if I chose to ditch them so expect maybe £1-1.5k more than the other two options. https://www.bimblesolar.com/ongrid/5kVA ... -ESS-14kwh

I'd be interested to hear if anyone has something similar to the Victron setup and whether that might be a better option going forward. If I added another couple of batteries, up to 17.5kwh, the Victron system would still be able to manage charging it in the same time periods I think.

Thoughts?

[Countrypaul]

Hi Paul, thanks for the thought about the Eddi and the heat pump. I looked at it at the time but I think we decided that as the heat pump runs the hot water, there wouldn't be much extra input from the heat pump itself as the temperature for DHW is set lower than the immersions and the heat pump tends to keep the tank topped up during the day. The Eddi will throw extra energy into the tank and take it higher than the heat pump would. At least, I think that's what was said at the time of the install.

You are in a simialr position to me (Eddi and HP) and at present we do exactly the same as you. In future if we get a battery, then a decision will have to be made on whether to top up the battery first or the DHW. If you can get 3 times as much heat out of the HP than you can with the immersion you might find it becoes worthwhile revisiting. We also have out UFH set to ensure the house is warm at 07:30, and have the thermostats set slightly lower after 07:30. This usually results in the HP not runing during the day - and in 4 months last year it did not run at all. I am considering turning the HP output temperature up for that period and having the Eddi turn the HP on (should also be a higher COP as its an ASHP) as that will maximise the efficiency of the water heating, with the Eddi doing the last bit of lifting the temp above what the HP will do.

[SafetyThird]

Yes, definitely something to consider in the future, particularly with the move to adding batteries to the mix. Shouldn't be too hard to implement if it looks to be necessary. Might need to look into getting the heat pump connected to the network as currently everything is controlled by going outside to the cupboard and poking the control panel.

[SafetyThird]

Sent a meter readying this morning and had a bill back within an hour.

4/11/21-31/3/22, 4946kwh day rate, 1748kwh night rate, cost of £1624. So, 45kwh/day at a cost of £11. Battery pack id definitely the way to go for now, probably about 10kwh for now and expand as we can afford up to about 20kwh. My aim with the combination of the battery pack and change in tariff is to reduce the annual bill by £1000, though it might end up being more with the costs going up the way they are, which would give a payback time of about 6 years.

Now, back to the battery pack research

[Swwils]

I wouldn't even bother with givenergy, it feels like a product you never truly "own" and you are one firmware update away from it not working.

Pylontech is kind of the oppersite, which is attractive to some people. We should probably organise a group buys especially the new 5000s.

If you can find an installer the new Huawei battery modules are interesting purely because each is independent so you can quite quickly build up a very large discharge rate if your DNO (and budget) has allowed it.

For inverter, I am a big fan of the cheap as possible strategy. Just replace it if it goes pop. Any monitoring can be done with superior standalone systems like emon, although I have grown to like lux powers hybrid, it's very simple and works well